This document provides an overview of psychrometry and the psychrometric chart. It defines key terms like dry bulb temperature, wet bulb temperature, humidity ratio, enthalpy and others. It explains common HVAC processes that can be analyzed using the psychrometric chart, such as sensible cooling/heating, humidification, dehumidification. The document also provides examples of using the psychrometric chart to analyze real HVAC processes and case studies. Mastering the psychrometric chart and properties of moist air is essential for properly designing and troubleshooting HVAC systems.